There are several reasons that inkjet printing has become a popular way of recording images on various media surfaces, particularly paper. Some of the reasons include low printer noise, capability of high-speed recording, and multi-color recording. Additionally, these advantages can be obtained at a relatively low price to consumers. However, although there has been great improvement in inkjet printing, accompanying this improvement are increased demands by consumers in this area, e.g., higher speeds, higher resolution, full color image formation, increased stability, more permanent images, etc.
In general, inkjet inks are either dye- or pigment-based inks. Both are typically prepared in a liquid vehicle that contains the dye and/or the pigment. Dye-based inkjet inks have been a dominant technology in the inkjet ink arena. However, as many dyes are water-soluble, images printed using many of such dye-based ink jet inks are not as water-fast as may be desirable. The water-fastness of an anionic dye-based inkjet ink printed on media has been shown to be enhanced by overprinting or underprinting the printed image with a fixer fluid including cationic material. Thus, when the cationic polymer and the anionic dye contact one another on a substrate, a reaction between the dye and the cationic material creates an image with improved water-fastness and permanence.
The most widely used cationic fixative in inkjet receptive coatings is poly(diallyldimethylammonium chloride), although other water-soluble cationic polymers are known, such as poly(vinylbenzylquaternary ammonium salts. Other examples include using calcium chloride as the fixing agent. For some of the solutions, a binder (coming from the ink dispersions) is typically required to improve the overall print durability.